Heat Recovery System

ABSTRACT

Additionally, the invention also relates to a method of assembly of a system having these features.

OBJECT OF THE INVENTION

The present invention relates to a heat recovery system comprising adevice which allows the connection between the elements of said system,such as a heat exchanger and an actuator controlling a valve of thepresent system. Said actuator is in turn configured such that itsoperation depends on the behavior of a substance due to the action ofthe temperature of a fluid, for example the liquid coolant used in theheat exchanger of the system, wherein said heat exchanger is arranged inan exhaust duct of an internal combustion engine.

Additionally, the invention also relates to a method of assembly of asystem having these features.

BACKGROUND OF THE INVENTION

One of the fields of the art that has been subjected to the mostintensive development is the field of heat recovery systems in vehicleswith an internal combustion engine.

In particular, said heat recovery systems are configured with theattachment of different elements, such as a heat exchanger, an exhaustduct, and a valve, allowing the heat recovery device, depending on theposition of said valve, to heat the coolant of the internal combustionengine, or not, by the action of the exhaust gas. An actuator, alsocomprised in the heat recovery system, allows control over the valve.

The attachments between different elements of the system, particularlybetween the heat exchanger and the actuator, are established today bymeans of connections involving additional parts, for example flexibletubing, metal tubing, or independent manifolds, which do allow the fluidattachment between elements but in turn entail complex connections.

These complex attachments entail various drawbacks, such as the presenceof additional parts occupying a larger space, the possibility of leakagein the connections between parts, and the risk of requiring higherassembly tolerances that do not allow suitable fitting between parts.

The present invention solves these problems by proposing a systemprovided with a coupling device which allows a more compact and robustattachment of the elements of said heat recovery system, therebypreventing possible fluid leakage and providing better assemblytolerances.

Additionally, the method of assembly also object of the presentinvention allows obtaining a heat recovery system having these features.

DESCRIPTION OF THE INVENTION

A first aspect of the invention relates to a heat recovery system,comprising:

-   -   an exhaust duct,    -   a heat exchanger for the exchange of heat between a hot gas        coming from the exhaust duct and a liquid coolant, comprising at        least one fluid connection for the entry/exit of the liquid        coolant,    -   a valve actuated through a shaft for opening or closing the        passage of hot gas through the heat exchanger,    -   an actuator comprising a drive rod actuated by a substance the        specific volume of which changes in the event of changes in        temperature, the actuator further comprising:        -   an inlet/outlet port for the entry/exit of a fluid;        -   an internal chamber in fluid communication with the            inlet/outlet port and in thermal communication with the            substance such that in operating mode, the substance is in            thermal communication with the fluid entering the internal            chamber through the inlet/outlet port;

One of the main elements of the present heat recovery system is a heatexchanger, whereby the exhaust gas is cooled upon the exchange of heatwith the fluid coolant, said coolant in turn therefore being heated, aswell as an exhaust duct through which all of the exhaust gas from theinternal combustion engine flows in the event that it is not cooled. Thehot gas comes from the engine and flows through the exhaust duct, theadditional passage thereof through the inside of the heat exchangerbeing possible for cooling thereof.

The heat recovery system in turn comprises a valve, wherein the flapcontrolled by the shaft of said valve allows, or not, depending on itsarrangement, the passage of the exhaust gas through the heat exchanger,which allows the cooling, or not, of said exhaust gas, and therefore thecorresponding heating of the coolant.

This valve is controlled by the actuator which, in this case, isoperated based on the behavior with respect to the temperature of asubstance contained in said actuator.

The specific volume of said substance changes as a response to thetemperature of a fluid with which it is in contact, said fluid being theliquid coolant circulating through the heat exchanger.

The liquid coolant can, interchangeably, exchange heat first with thesubstance in the internal chamber located inside the actuator, and thenwith the exhaust gas inside the heat exchanger, or vice versa.

The system according to the first aspect of the invention additionallycomprises:

-   -   a metallic fluid coupling device, attached at a first fluid        inlet/outlet by means of welding to the at least one fluid        connection of the heat exchanger and at a second fluid        outlet/inlet to the inlet/outlet port of the actuator such that        a fluid connection is established between the inlet/outlet port        of the actuator and the fluid connection of the heat exchanger        through the fluid coupling device, and        wherein the drive rod of the actuator is connected with the        shaft of the valve for the actuation thereof according to the        temperature of the liquid coolant.

The present metallic fluid coupling device is attached to both the heatexchanger and the actuator, such that the liquid coolant is capable offlowing through said metallic fluid coupling device from the heatexchanger to the actuator or vice versa.

Advantageously, the attachment of the heat exchanger and the actuatorthrough the metallic fluid coupling device allows said actuator to fixits position with respect to the exchanger.

In a particular embodiment, the metallic fluid coupling device acts likea structural element and allows supporting the actuator such that theneed to incorporate additional parts, for example brackets, which holdthe actuator in its position with respect to the heat exchanger, isprevented.

An attachment by means of the metallic fluid coupling device therebyallows reducing the parts that were previously required, therebyresulting in a more lightweight and more compact system.

Additionally, since the fluid coupling device is a metallic device, itallows preventing any risk of deterioration due to the action of hightemperatures and heat, unlike the fluid coupling devices of the state ofthe art, which usually consist of flexible rubber tubing.

In a particular embodiment, the metallic fluid coupling device ismanufactured from stamped metal sheet, preferably punched and stampedmetal sheet.

In a particular embodiment, said metallic fluid coupling device isconfigured by a plurality of parts, which allows the fitting betweensaid parts, as well as with the actuator and the heat exchanger, to beeven more precise.

In a particular embodiment, wherein the metallic fluid coupling deviceis configured by a plurality of parts, specifically a configuration oftwo different parts, this device comprises:

-   -   a first part comprising:        -   a first support region;        -   a first inner space with a first opening wherein the first            opening is peripherally demarcated by the first support            region;        -   the first fluid inlet/outlet of the metallic fluid coupling            device;    -   a second part comprising:        -   a second support region;        -   a second inner space with a second opening wherein the            second opening is peripherally demarcated by the second            support region;        -   the second fluid outlet/inlet of the metallic fluid coupling            device;            wherein:    -   the first support region and second support region are attached    -   the first fluid inlet/outlet is in fluid communication with the        second inner space,    -   the second fluid outlet/inlet is in fluid communication with the        first inner space, and    -   the first inner space and second inner space are in fluid        communication through the first and second openings.

This particular embodiment alone constitutes a second aspect of theinvention which is described in the embodiments as a specific solutionapplied to the first inventive aspect.

The present configuration allows a direct connection of the exchangerand actuator, and therefore a closed circuit for the coolant, throughthe attachment of the first part and second part by means of theirsupport regions and the overlapping of the first opening and secondopening.

These first and second support regions are, preferably, flat regionswhich allow their attachment to occur through a common plane defining acontact surface. In turn, the first opening and second opening are areaslimiting the first inner space and second inner space, respectively.Said limitation occurs on the plane of each of the support regions,since each of the openings is defined and limited on the plane of eachcorresponding support region.

Additionally, in a particular example of the second inventive aspect,the attachment of the first support region and second support region isconfigured as follows:

-   -   before the attachment, the first support region and second        support region establish a sliding support with one support        region on top of the other support region, such that the first        inner space is in fluid communication with the second inner        space; and    -   after the attachment between the first support region and second        support region, the attachment establishes the leak-tight        closure of the space generated by the attachment of the first        inner space and second inner space and the fluid communication        between the first fluid inlet/outlet and second fluid        outlet/inlet.

Said sliding support allows the absorption of the necessary tolerancesrelating to the manufacture and assembly of the present system. Afterthe attachment of said regions, the support generated between bothsupport regions is fixed, the closure being leak-tight and thereforepreventing any type of coolant leakage as it passes through the metallicfluid coupling device between the actuator and heat exchanger.

Preferably, the metallic fluid coupling device comprises, between thefirst support region and second support region, a closed perimetercontact area with an internal passage through which the first innerspace communicates with the second inner space.

Said perimeter contact area is contained on the common plane generatedfrom the attachment of both support regions, whereas the internalpassage is defined by the overlap existing between the first opening andsecond opening contained in each of the support regions and peripherallylimited by same.

Preferably, the attachment between the first part and second part of themetallic fluid coupling device through the first and second supportregions is established by welding.

In a particular example, the first inner space of the first part isconcave, the second inner space of the second part is concave, and afterthe attachment of the first support region and second support region ofthe metallic fluid coupling device, the concavity of the first innerspace is opposite to the concavity of the second inner space.

Said concave inner spaces allow defining a path for the fluid coolantupon the passage thereof through the metallic fluid coupling device,said device thereby being more compact.

Preferably, the space generated by the attachment of the first innerspace and second inner space for fluid communication between theopenings which allow the entry and exit of the coolant in the metallicfluid coupling device is configured according to a zigzag-type conduit,preferably a tubular zigzag-type conduit, which allows reducing thedimensions of the metallic fluid coupling device.

In a particular embodiment, the inlet/outlet port of the actuator isfluidically connected with the second fluid outlet/inlet of the secondpart of the metallic fluid coupling device, and wherein the first fluidinlet/outlet of the first part of the metallic fluid coupling device isfurthermore fluidically connected with the fluid connection of the heatexchanger.

Additionally, the actuator has a second outlet/inlet port connected tothe cooling circuit of the internal combustion engine.

Each of the plates forming the metallic fluid coupling devices isthereby connected with one of the elements of the system, thus formingthe circuit through which the coolant circulates.

Therefore, the second part of the device allows supporting the actuator,with the weight being transmitted through the first part of the device,connected with the heat exchanger, which is what supports the remainingparts of the system.

Preferably, the mentioned connections are established by means ofwelding, more preferably by brazing.

In a particular embodiment, the thermal substance of the actuator iswax, and the rod is in a first position when the temperature of thefluid accessing its interior through its inlet port is at a temperaturebelow a pre-established value, and extends to a second position when thetemperature of the fluid accessing its interior through its inlet portexceeds said pre-established value.

A third inventive aspect relates to a method of assembly of a systemaccording to the first inventive aspect, which method comprises carryingout the following steps a) to d) in any order:

-   -   a) building the heat exchanger with the fluid connection for the        liquid coolant, the exhaust duct, and the valve actuated through        a shaft for opening or closing the passage of hot gas;    -   b) building the actuator with the drive rod and the inlet/outlet        port;    -   c) attaching the fluid connection of the heat exchanger with the        metallic fluid coupling device by means of welding;    -   d) attaching the inlet/outlet port of the actuator with the        fluid coupling device by means of welding.

Advantageously, the present method of assembly allows obtaining acompact system, wherein a lower number of parts is needed to form saidheat recovery system, which allows said recovery device to occupy lessspace.

For the particular embodiment in which the metallic fluid couplingdevice is configured from a first part and second part, the method ofassembly is modified as follows:

-   -   step c) comprises attaching the fluid connection of the heat        exchanger with the second part of the metallic coupling device        by means of welding, and    -   step d) comprises attaching the inlet/outlet port of the        actuator with the first part of the metallic coupling device by        means of welding, and    -   wherein the following steps are carried out sequentially after        step d):    -   e) placing the assembly formed by the heat exchanger and the        second part with respect to the second assembly formed by the        actuator and the first part such that the first support region        of the first part and the second support region of the second        part are in sliding contact, and    -   f) attaching the first part of the metallic fluid coupling        device and the second part of the device.

Particularly, the movement between the first position of the rod and thesecond position of the rod of the actuator establishes theopening/closing of the valve.

This advantageously enables the additional attachment between both partsof the metallic fluid coupling device to maintain the leak-tightness ofsaid device, while at the same time it enables greater flexibility forabsorbing tolerances in the assembly of the system.

Preferably, each of the mentioned attachments is established by means ofbrazing.

DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention willbecome more apparent based on the following detailed description of apreferred embodiment given only by way of illustrative and non-limitingexample in reference to the attached drawings.

FIG. 1 shows a diagram of a particular embodiment of the systemaccording to the first inventive aspect.

FIG. 2 shows a perspective view of a system according to the secondinventive aspect, according to a particular embodiment thereof.

FIGS. 3A/3B show a front view and section view, respectively, of asystem according to the same particular embodiment as FIG. 2.

FIGS. 4A-4B show a perspective view as well as a section view of aparticular example of a metallic fluid coupling device.

FIGS. 4C-4D show a perspective view of each part of the metallic fluidcoupling device of FIGS. 4A and 4B.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a diagram in which a particular example of a system (4)like the one of the first inventive aspect of the present application isdefined.

Said system (4) is formed by a tube heat exchanger (6) through whichtubes there circulates an exhaust gas coming from the exhaust duct (8),and therefore from the internal combustion engine of the vehicle, aswell as an actuator (7) which, by means of a rod (7.2), allows theoperation of the shaft (5) of a valve not shown in the present figure.This operation involves the change in position of the flap of the valve,allowing passage of the exhaust gas through the heat exchanger (6) in afirst position, such that this may heat up the coolant circulatingoutside the tubes (while at the same time it is cooled by said coolant),or allowing passage of all of the exhaust gas through the exhaust ductor bypass duct (8) in a second position, thereby preventing the heatingof the coolant by said exhaust gas as the latter is expelled directlyinto the atmosphere.

The attachment between the actuator (7) and the heat exchanger (6) isestablished through an intermediate element, a metallic fluid couplingdevice (1), which allows supporting said actuator (7) on the exchanger(6).

In particular, a first fluid inlet/outlet (1.1) of the metallic fluidcoupling device (1) is attached to the fluid connection through whichthe coolant enters/exit the heat exchanger (6), whereas a second fluidoutlet/inlet (1.2) of the metallic fluid coupling device (1) is attachedto the inlet/outlet port (7.1) through which said coolant enters/exitsthe actuator (7).

A closed circuit is thereby formed for the liquid coolant circuit which,in this case, goes from the actuator (7), where it causes the operationof the rod (7.2) by the action of its temperature on the substance ofthe actuator (7), through the metallic fluid coupling device (1), to theheat exchanger (6), in order to thereby cool the exhaust gas goingthrough the tubes of said exchanger (6).

In an additional particular example, this circuit could be configured inthe opposite manner, the liquid coolant thereby flowing from the heatexchanger (6) to the actuator (7).

FIG. 4A shows a perspective view of a particular example of a metallicfluid coupling device (1), particularly formed by a first part (2) and asecond part (3) which are attached to one another through a flat surfaceof each of the two parts (2, 3), thereby forming an internal path bymeans of concave cavities in each of these parts (2, 3) which allow theliquid coolant to pass therethrough.

FIG. 4B shows a section of this same metallic fluid coupling device (1),wherein the parts (2, 3) comprise a first inner space (2.1, 3.1),respectively, or internal cavity through which the coolant circulates asit passes through the device (1).

The liquid coolant accesses the metallic fluid coupling device (1)through the second fluid inlet (1.2) of the device (1) from the actuator(7), and it exits said device (1) towards the exchanger (6) through thefirst fluid outlet (1.1). In other words, access of the coolant to thedevice (1) occurs through the second fluid inlet (1.2) located in thesecond part (3), in fluid connection with the actuator (7), and itsaccess from the device (1) to the exchanger (6) occurs through the firstfluid outlet (1.1) located in the first part (2) forming the device (1).

As shown in FIGS. 4C and 4D, which show a perspective view of each ofthe parts (2, 3) forming the device (1), each part (2, 3) has a flatsupport region (2.2, 3.2), respectively. Said attachment of parts (2, 3)is shown in FIGS. 4A and 4B, being welded to one another by means ofbrazing to achieve closure of the device (1), thereby preventing leakageof the coolant as it passes through said device (1).

Additionally, FIG. 4C shows the first inner space (2.1) of the firstpart (2), which is demarcated by the first opening (2.1.1).

The first fluid inlet/outlet (1.1) is, in turn, a punched opening on thefirst part (2).

The first support region (2.2) peripherally demarcates both the firstfluid inlet/outlet (1.1) and the first opening (2.1.1).

Similarly, FIG. 4D shows the second inner space (3.1) of the second part(3), which is demarcated by the second opening (3.1.1).

The second fluid outlet/inlet (1.2) is, in turn, a punched opening onthe second part (3).

The second support region (3.2) peripherally demarcates both the secondfluid outlet/inlet (1.2) and the second opening (3.1.1).

FIGS. 2, 3A, and 3B show perspective, front, and section views,respectively, of an already assembled complete heat recovery system (4).

In that sense, a tube heat exchanger (6) as well as the adjacent exhaustduct (8) through which the exhaust gas circulates, following the pathdemarcated by the valve comprised in the system (4), can be seen in saiddrawings.

An actuator (7) is arranged on the exchanger (6), such that it allowscontrolling the shaft (5) of the valve which offers access of theexhaust gas to the exchanger (6) itself at all times.

In this particular example, the actuator (7) is a wax actuator, this waxbeing a substance contained in the internal chamber (7.4) of theactuator (7) which, by means of reacting to the temperature upon contactwith the coolant, operates the rod (7.2) on the shaft (5) of the valve.

The fluid connection which allows the passage of the coolant from theexchanger (6) to the actuator (7) is established through the metallicfluid coupling device (1) configured from two parts (2, 3) attached byrespective support regions (2.2, 3.2), as can be seen in FIG. 3A.

As shown in FIG. 3B, the heat exchanger (6) has a fluid connection (6.1)which allows the passage of the fluid coolant, in this case coming fromthe actuator (7). In order to allow access of said fluid coolant, theactuator (7) has an outlet port (7.1), in connection with the metallicfluid coupling device (1), and in particular with the second part (3) ofsaid device (1), which allows the fluid coolant to flow from theactuator (7) to the device (1), and from the latter to the exchanger (6)through the fluid connection (6.1).

As can be seen in FIG. 3B, the outlet port (7.1) is therefore in fluidconnection with the second fluid inlet/outlet (1.2) of the device (1),whereas the fluid connection (6.1) is fluidically connected with thefirst fluid inlet/outlet (1.1) of the device (1).

FIG. 3A shows a spigot (7.3) as part of the actuator (7) from which theliquid coolant comes, said spigot (7.3) being fluidically connected withthe cooling circuit of the engine (not shown).

1. A system (4) comprising: an exhaust duct (8), a heat exchanger (6)for the exchange of heat between a hot gas coming from the exhaust duct(8) and a liquid coolant, comprising at least one fluid connection (6.1)for entry/exit of the liquid coolant, a valve actuated through a shaft(5) for opening or closing the passage of hot gas through the heatexchanger (6), an actuator (7) comprising a drive rod (7.2) actuated bya substance the specific volume of which changes in the event of changesin temperature, the actuator (7) further comprising: an inlet/outletport (7.1) for the entry/exit of a fluid; an internal chamber (7.4) influid communication with the inlet/outlet port (7.1) and in thermalcommunication with the substance such that in operating mode, thesubstance is in thermal communication with the fluid entering theinternal chamber (7.4) through the inlet/outlet port (7.1); a metalfluid coupling device (1), attached at a first fluid inlet/outlet (1.1)by means of welding to the at least one fluid connection (6.1) of theheat exchanger (6) and at a second fluid outlet/inlet (1.2) to theinlet/outlet port (7.1) of the actuator (7) such that a fluid connectionis established between the inlet/outlet port (7.1) of the actuator (7)and the fluid connection (6.1) of the heat exchanger (6) through thefluid coupling device (1), and wherein the drive rod (7.2) of theactuator (7) is connected with the shaft (5) of the valve for theactuation thereof according to the temperature of the liquid coolant. 2.The system (4) according to claim 1, wherein the metallic fluid couplingdevice (1) is made of stamped metal sheet.
 3. The system (4) accordingto claim 1, wherein the metallic fluid coupling device (1) is astructural element which supports the actuator (7).
 4. The system (4)according to claim 1, wherein the metallic fluid coupling device (1)comprises a plurality of parts.
 5. The system (4) according to claim 4,wherein the metallic fluid coupling device (1) comprises: a first part(2) comprising: a first support region (2.2); a first inner space (2.1)with a first opening (2.1.1) wherein the first opening (2.1.1) isperipherally demarcated by the first support region (2.2); the firstfluid inlet/outlet (1.1) of the metallic fluid coupling device (1); asecond part (3) comprising: a second support region (3.2); a secondinner space (3.1) with a second opening (3.1.1) wherein the secondopening (3.1.1) is peripherally demarcated by the second support region(3.2); the second fluid outlet/inlet (1.2) of the metallic fluidcoupling device (1); wherein: the first support region (2.2) and secondsupport region (3.2) are attached, the first fluid inlet/outlet (1.1) isin fluid communication with the second inner space (3.1), the secondfluid outlet/inlet (1.2) is in fluid communication with the first innerspace (2.1), and the first inner space (2.1) and second inner space(3.1) are in fluid communication through the first opening (2.1.1) andsecond opening (3.1.1).
 6. The system (4) according to claim 5, whereinthe attachment of the first support region (2.2) and second supportregion (3.2) is configured as follows: before the attachment, the firstsupport region (2.2) and second support region (3.2) establish a slidingsupport with one support region (2.2) on top of the other support region(3.2), such that the first inner space (2.1) is in fluid communicationwith the second inner space (3.1); and after the attachment between thefirst support region (2.2) and second support region (3.2), theattachment establishes the leak-tight closure of the space generated bythe attachment of the first inner space (2.1) and second inner space(2.1) and the fluid communication between the first fluid inlet/outlet(1.1) and second fluid outlet/inlet (1.2).
 7. The system (4) accordingto claim 5, wherein the first support region (2.2) and second supportregion (3.2) of the metallic coupling device (1) are flat.
 8. The system(4) according to claim 5, wherein the first inner space (2.1) of thefirst part (2) is concave, the second inner space (3.2) of the secondpart (3) is concave, and after the attachment of the first supportregion (2.2) and second support region (3.2) of the metallic fluidcoupling device (1), the concavity of the first inner space (2.1) isopposite the concavity of the second inner space (3.2).
 9. The system(4) according to claim 5, wherein the attachment between the first part(2) and second part (3) of the metallic fluid coupling device (1) ismade by welding.
 10. The system (4) according to claim 5, wherein thespace generated by the attachment of the first inner space (2.1) andsecond inner space (3.1) for fluid communication between the first fluidinlet/outlet (1.1) and second fluid outlet/inlet (1.2) of the metallicfluid coupling device (1) is configured according to a zigzag-typeconduit.
 11. The system (4) according to claim 5, wherein theinlet/outlet port (7.1) of the actuator (7) is fluidically connectedwith the second fluid outlet/inlet (1.2) of the second part (3) of themetallic fluid coupling device (1), and wherein the first fluidinlet/outlet (1.1) of the first part (2) of the metallic fluid couplingdevice (1) is furthermore fluidically connected with the fluidconnection (6.1) of the heat exchanger (6).
 12. A method of assembly ofa system (4) according to claim 1, which method comprises carrying outthe following steps a) to d) in any order: a) building the heatexchanger (6) with the fluid connection (6.1) for the liquid coolant,the exhaust duct (8), and the valve actuated through a shaft (5) foropening or closing the passage of hot gas; b) building the actuator (7)with the drive rod (7.2) and the inlet/outlet port (7.1); c) attachingthe fluid connection (6.1) of the heat exchanger (6) with the metallicfluid coupling device (1) by means of welding; d) attaching theinlet/outlet port (7.1) of the actuator (7) with the fluid couplingdevice (1) by means of welding.
 13. The method of assembly according toclaim 12, wherein step c) comprises attaching the fluid connection (6.1)of the heat exchanger (6) with the second part (3) of the metalliccoupling device (1) by means of welding, and step d) comprises attachingthe inlet/outlet port (7.1) of the actuator (7) with the first part (2)of the metallic coupling device (1) by means of welding, and wherein thefollowing steps are carried out sequentially after step d): e) placingthe assembly formed by the heat exchanger (6) and the second part (3)with respect to the second assembly formed by the actuator (7) and thefirst part (2) such that the first support region (2.2) of the firstpart (2) and the second support region (3.2) of the second part (3) arein sliding contact, f) attaching the first part (2) of the metallicfluid coupling device (1) and the second part (3) of the device.
 14. Themethod of assembly according to claim 12, wherein the attachments areestablished by means of brazing.